magnetic fields and phase noise?

[Fraser Robertson]

Interesting Earl, the non exhaustive tests I've done indicate that it is not
due to magnetic fields.  But if indeed that is the case, there must be a
relatively easy, if perhaps not elegant, way of significantly improving
this.

Has anyone else investigated this?

73 Fraser G4BJM

>From: Earl W Cunningham <[hidden email]>

>Over a year ago I noticed this problem, which occurs only when my K2 is
>driving my Alpha linear.  After extensive testing done by me to determine
>the cause of the problem, is was found to be caused by hum from the
>magnetic field of the linear amplifier's HV transformer getting into the
>PLL circuit of the K2.  In my case, 6 feet of separation between the K2
>and the linear was not enough to eliminate the problem, however with 30
>feet of separation (with the K2 and amp in separate rooms) did solve the
>problem.  This answer is unacceptable, of course.
>

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[S55M]

Hello!

Maybe changing the alluminium cover plates with some other material would
solve some of the problems at expense of K2 "lighthness".
The only problem are the front plate and the rear plate(basic K2 without
100W PA) which are not so easy to perforate.

And i perfectly agree with Geoff!
When there is a debate abot ESD soldering stations keyers ecc everyione add
2c but on tehnical problems "no takers" HI.

Adi
----- Original Message -----
From: "Fraser Robertson" <[hidden email]>
To: <[hidden email]>; <[hidden email]>; <[hidden email]>
Sent: Saturday, March 19, 2005 11:26 AM
Subject: [Elecraft] magnetic fields and phase noise?


> Interesting Earl, the non exhaustive tests I've done indicate that it is
not

> due to magnetic fields.  But if indeed that is the case, there must be a
> relatively easy, if perhaps not elegant, way of significantly improving
> this.
>
> Has anyone else investigated this?
>
> 73 Fraser G4BJM
>
> >From: Earl W Cunningham <[hidden email]>
>
> >Over a year ago I noticed this problem, which occurs only when my K2 is
> >driving my Alpha linear.  After extensive testing done by me to determine
> >the cause of the problem, is was found to be caused by hum from the
> >magnetic field of the linear amplifier's HV transformer getting into the
> >PLL circuit of the K2.  In my case, 6 feet of separation between the K2
> >and the linear was not enough to eliminate the problem, however with 30
> >feet of separation (with the K2 and amp in separate rooms) did solve the
> >problem.  This answer is unacceptable, of course.
> >
>
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[Vic K2VCO]

Fraser Robertson wrote:

> Interesting Earl, the non exhaustive tests I've done indicate that it is
> not due to magnetic fields.  But if indeed that is the case, there must
> be a relatively easy, if perhaps not elegant, way of significantly
> improving this.
>
> Has anyone else investigated this?

I have an Alpha 86 which is about 3 feet from my K2.  I have performed tests in
which someone listened to my signal at 100 watts and 1.3 KW without noticing any
difference in quality.  I'd be glad to sked Earl or anyone else who wants to try
this (unfortunately I am in the process of working on my 160/80 meter antennas,
so it would have to be 40 meters or higher).

--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco

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[Earl W Cunningham]

Worked Vic, K2VCO this morning on 40m CW.  His K2/100 was absolutely
clean with no clicks and no noise on his CW sidebands while he was
running barefoot.

When he ran ran QRO to his Alpha 87A, There were still no clicks, however
there was noise on his sidebands extending out +/- about 1 kHz from
center frequency.  I honestly expected it to be worse than that, but he
apparently also has the same problem with the magnetic field from the
magnetic field from the HV xfmr in his amp getting into his K2.

I was using my IC-756Pro3 with a 50 Hz bandwidth.  Tuning off to either
side of Vic's CW signal where the tone disappeared, you could still copy
him due to the noise on his sidebands.

Anyone with a K2 driving a linear amp can easily check for this by
listening on a separate receiver using the narrowest bandwidth available
by tuning the signal just out of the receiver passband while transmitting
on the K2 with amp.  It sounds like noisy sidebands on the transmitted CW
signal.

With my K2, the problem occurs on all bands.  It doesn't occur when I use
any of my other transceivers (IC-756Pro3, FT-1000MP, TS-830S).

73, de Earl, K6SE
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[Vic K2VCO]

Earl W Cunningham wrote:

> Worked Vic, K2VCO this morning on 40m CW.  His K2/100 was absolutely
> clean with no clicks and no noise on his CW sidebands while he was
> running barefoot.
>
> When he ran ran QRO to his Alpha 87A, There were still no clicks, however
> there was noise on his sidebands extending out +/- about 1 kHz from
> center frequency.  I honestly expected it to be worse than that, but he
> apparently also has the same problem with the magnetic field from the
> magnetic field from the HV xfmr in his amp getting into his K2.

My K2 is about 4 feet from the Alpha 86 (not 87A unfortunately) and it's on the
side near the hypersil transformer.  If this is indeed caused by the magnetic
field, I suspect that there is a particular component or components that are
affected, and perhaps it would be possible to shield them.  I rarely run more
than 100 watts, but there are times that I would like to do so, so I'll be
looking for a solution.

--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco



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[Geoffrey Mackenzie-Kennedy-2]

Sorry, I had to post twice.
Geoff
GM4ESD


----- Original Message -----
From: "Geoffrey Mackenzie-Kennedy" <[hidden email]>
To: "Earl W Cunningham" <[hidden email]>
Sent: Sunday, March 20, 2005 7:41 PM
Subject: Re: [Elecraft] magnetic fields and phase noise?


> Earl,
> How strong was Vic's carrier at your Pro3 when he was QRO with the 87A,
and

> how far down were the sidebands? Not thinking of Rx problems at all, just
> trying to get an accurate pictue of Vic's QRO signal.
> 73,
> Geoff.
> GM4ESD
>
>
> ----- Original Message -----
> From: "Earl W Cunningham" <[hidden email]>
> To: <[hidden email]>; <[hidden email]>
> Sent: Sunday, March 20, 2005 6:13 PM
> Subject: Re: [Elecraft] magnetic fields and phase noise?
>
>
> > Worked Vic, K2VCO this morning on 40m CW.  His K2/100 was absolutely
> > clean with no clicks and no noise on his CW sidebands while he was
> > running barefoot.
> >
> > When he ran ran QRO to his Alpha 87A, There were still no clicks,

however

> > there was noise on his sidebands extending out +/- about 1 kHz from
> > center frequency.  I honestly expected it to be worse than that, but he
> > apparently also has the same problem with the magnetic field from the
> > magnetic field from the HV xfmr in his amp getting into his K2.
> >
> > I was using my IC-756Pro3 with a 50 Hz bandwidth.  Tuning off to either
> > side of Vic's CW signal where the tone disappeared, you could still copy
> > him due to the noise on his sidebands.
> >
>

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